Glass ball

For industrial applications (e.g., check valves, bearings), focus on sphericity (roundness tolerance) and surface roughness (Ra). Common materials include Borosilicate glass for thermal resistance and Soda-lime glass for general use. For decorative or optical use, prioritize refractive index, clarity (absence of bubbles/inclusions), and K9 crystal quality. Ensure the diameter tolerance meets your specific mechanical requirements, typically within ±0.001mm to ±0.05mm depending on the grade.

If the glass balls are used in toys (marbles), they must comply with EN71 (Europe) or ASTM F963 (USA) regarding physical safety and heavy metal content. For laboratory or food-contact use, ensure they meet FDA (Food and Drug Administration) or LFGB standards. For industrial components, ISO 9001 certification of the manufacturer is essential to ensure batch-to-batch consistency and traceability.

Request a chemical composition analysis report. Borosilicate 3.3 glass is superior for resisting acid and alkaline corrosion. For mechanical durability, ask for compressive strength test results and Mohs hardness ratings (typically 5-7). If the product is for outdoor use, verify UV stability and thermal shock resistance to prevent cracking during temperature fluctuations.

Suppliers on Made-in-China.com often offer precision grinding, polishing, and drilling (half-hole or through-hole). You can also request color customization (solid or transparent), sandblasting for matte finishes, or laser engraving for branding. For high-precision needs, specify the Grade (e.g., Grade 100, 200, or 1000) which dictates the allowable diameter variation.

Glass balls are high-density and fragile. Insist on double-wall corrugated export cartons with EPE foam inserts or vacuum-sealed plastic bags to prevent friction. For bulk shipments, palletization with shrink wrap and corner protectors is mandatory. Ensure the Incoterms include CIF (Cost, Insurance, and Freight) or purchase separate cargo insurance to cover potential transit damage.

Focus on volume-based pricing tiers; glass production is energy-intensive, so larger runs significantly lower the unit cost. Ask for a sample refund policy where the cost of the prototype is deducted from the first mass-production order. On Made-in-China.com, look for Audited Suppliers to leverage their verified production capacity as a negotiation point for shorter lead times.

Always use secure payment methods such as Letters of Credit (L/C) for large volumes or Escrow-based services provided by reputable platforms. Conduct a third-party factory audit or a Pre-Shipment Inspection (PSI) to verify that the quantity and quality match the Proforma Invoice before the final balance is paid.

Due to the high weight-to-volume ratio, Sea Freight (LCL or FCL) is the most economical choice for bulk orders. For small precision batches or urgent samples, Air Freight is viable but expensive. Ensure your supplier provides a Material Safety Data Sheet (MSDS) if the glass balls are coated with any chemical substances to avoid customs delays.